Amy Sheng can sum up in one sentence why it’s important to have more female scientists and engineers designing products — especially if those products involve childbirth or breastfeeding: “A guy cannot fundamentally understand,” she says.

A Stanford-educated mechanical engineer, Sheng was reacting to recent efforts, including a hackathon M.I.T. held in September to come up with a better breast pump. But the sentiment also applies to her own company’s invention, which is aimed chiefly at moms.

Sheng is a co-founder of CellScope, a smart-phone attachment that allows parents to take videos of a child’s inner ear that can then be sent to doctors for an ear-infection diagnosis. She began working on the idea when she was pregnant — she now has two sons under the age of four. “I personally experienced the pain point,” she says. “My child is screaming and sick, and the pediatrician’s office is closed because it’s 9 o’clock at night. From an entrepreneur’s perspective, there is nothing better than being an actual user.”

The fact that fewer women found start-ups around science and new technologies is a concern to nonprofits like the Kauffman Foundation and corporations like 3M, Merck and Dell (and even the White House). When female perspectives are left out, innovations tend to be male-centric, often overlooking the needs or desires of women.

“When new companies and industries flourish, everyone benefits,” according to a Kauffman report, “Overcoming the Gender Gap.” “And the returns will increase when more women contribute to the process by bringing their ideas to market and building high-growth firms around them.”

Women who are pursuing start-ups in tech or science say they’re often inspired to create products that they — as consumers — would use. In San Francisco, Leah Sparks and Katherine Bellevin are developing Due Date Plus, a smart phone-enabled maternity program. Surbhi Sarna of nVision, who suffered from ovarian cysts, is working on devices to detect ovarian cancer and tube blockages.

Barriers remain high, however. Most of the venture capitalists who finance start-ups in the STEM fields are men who don’t always understand or feel comfortable with women-centric technologies. Sarna, who has raised $4.5 million, says she stopped using the word “vagina” in her pitch, because it made men squirm. She didn’t have the same issue pitching to Astia Angels, a group that specializes in investing in women-led ventures.

Sheng, along with her co-founder Erik Douglas, has raised $5.6 million for CellScope, which was spun out of a research lab at University of California, Berkeley, in 2011. Before joining the lab, Sheng helped design an artificial heart at Abiomed and a microscope for blood smears at Medica, both in the Boston area. After moving back to San Francisco, her hometown, to be closer to family, she heard about Berkeley’s research lab, which was designing a microscope for remote diagnoses of tuberculosis and malaria in developing nations. She took a pay cut to join the lab. “It was the riskier and more uncertain path,” she says, “but I was definitely more excited by it.”

After two years, Sheng and Douglas decided to license the lab’s technology and form CellScope to focus on health care issues closer to home. Sheng says they knew from talking to parents that children’s ear infections were a major concern. CellScope, which now has 12 employees, plans to release its first smartphone otoscope early next year.

Unlike many women, Sheng says she was encouraged at an early age to pursue science. Her father, who worked in laser technology, flew planes and taught her about the physics of flying. Her mother was a scientist who took Sheng along on trips where she watched her mother present research at international conferences. Working in science and tech, she says, never seemed weird “because I saw my mom doing that.”

Sheng spent the last few years building a protoype for the otoscope, tweaking the design and signing up 800 doctors to use it. The physicians “were instrumental in helping us validate the quality of our product and providing feedback on how to improve,” she says.

In January, she plans a limited launch of the “Oto HOME” to consumers in California, selling the otoscope and its related software for $79. When parents use the device to take an ear exam, they can use the software to communicate with CellScope’s networks of doctors for a response. The fee will be $40 per remote diagnosis, she says.

The company also plans to sell a professional version for $300, which doctors can use in their own offices to show patients (or their parents) a digital video of the ear drum and explain diagnoses.

Sheng says the products will be sold directly from CellScope’s website, and the company has hired a business development manager to helped widen distribution to retail shelves. Initially, the focus will be on parents of childen who get three or more ear infections a year; she estimates nearly 5 million kids in the U.S. have chronic ear infections. The company plans to target such parents through social media, email campaigns and word-of-mouth marketing.

After years of tweaking her product’s technical design, Sheng says she is looking forward to tackling more business-related challenges. “Building something is one thing,” she says. “It’s another thing to figure out the model and how to monetize it.” But she thinks parents, especially moms, will be willing to pay for a quick diagnosis from the comfort of their own homes. “I would love to be a place where people will say, ‘I can’t believe that’s what you used to have to do for an ear infection.”